U.S. patent application number 12/485843 was filed with the patent office on 2010-03-18 for ductile metallic glasses.
This patent application is currently assigned to THE NANOSTEEL COMPANY, INC.. Invention is credited to Daniel James BRANAGAN, Brian E. MEACHAM, Alla V. SERGUEEVA.
Application Number | 20100065163 12/485843 |
Document ID | / |
Family ID | 41507373 |
Filed Date | 2010-03-18 |
United States Patent
Application |
20100065163 |
Kind Code |
A1 |
BRANAGAN; Daniel James ; et
al. |
March 18, 2010 |
DUCTILE METALLIC GLASSES
Abstract
This application deals with glass forming iron based alloys
which when produced as a metallic glass or mixed structure
comprising metallic glass and nanocrystalline phases, results in
extraordinary combinations of strength and ductility. Specifically,
high strain up to 97% and high strength up to 5.9 GPa has been
measured. Additionally, consistent with the amorphous structure
high elasticity up to 2.6% has been observed. Thus, the new alloys
developed result in structures and properties which yield high
elasticity corresponding to a metallic glass, high plasticity
corresponding to a ductile crystalline metal, and high strength as
may be observed in nanoscale materials.
Inventors: |
BRANAGAN; Daniel James;
(Idaho Falls, ID) ; MEACHAM; Brian E.; (Idaho
Falls, ID) ; SERGUEEVA; Alla V.; (Idaho Falls,
ID) |
Correspondence
Address: |
GROSSMAN, TUCKER, PERREAULT & PFLEGER, PLLC
55 SOUTH COMMERICAL STREET
MANCHESTER
NH
03101
US
|
Assignee: |
THE NANOSTEEL COMPANY, INC.
Providence
RI
|
Family ID: |
41507373 |
Appl. No.: |
12/485843 |
Filed: |
June 16, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61061768 |
Jun 16, 2008 |
|
|
|
Current U.S.
Class: |
148/561 ;
420/14 |
Current CPC
Class: |
C22C 1/02 20130101 |
Class at
Publication: |
148/561 ;
420/14 |
International
Class: |
C21D 6/00 20060101
C21D006/00; C22C 37/00 20060101 C22C037/00 |
Claims
1. A method of forming a ductile metallic material comprising:
providing a glass forming iron based metallic alloy comprising at
least 35 at % iron, nickel and/or cobalt present in the range of 7
at % to 50 at % and at least one element selected from the group
consisting of boron, carbon, silicon, phosphorous and nitrogen
present in the range of 1 at % to 35 at %, wherein said atomic
percent are selected to provide 95 atomic percent for a given
alloy; melting said glass forming iron based metallic alloy;
forming said glass forming alloy and cooling said alloy at a rate
of about 10.sup.2 to 10.sup.6 K/s forming a material comprising a
metallic glass, a nanocrystalline material or a mixture thereof;
wherein said material exhibits a strain of greater than 0.5%, a
failure strength in the range of 1 GPa to 5.9 GPa and a Vickers
hardness (HV300) of 9 GPa to 15 GPa.
2. The method of claim 1 wherein iron is present at 35 at % to 92
at %.
3. The method of claim 1 wherein said glass forming iron based
metallic alloy comprises 45 at % to 70 at % iron, 10 at % to 30 at
% Ni, 0 at % to 15 at % cobalt, 7 at % to 25 at % B, 0 at % to 6 at
% carbon and 0 at % to 2 at % silicon.
4. The method of claim 1 wherein said glass forming iron based
metallic alloy comprises 52 at % to 60 at % iron, 13 at % to 18 at
% nickel, 8 at % to 12 at % cobalt, 10 at % to 17 at % boron, 3 at
% to 6 at % C and 0.3 at % to 0.7 at % silicon.
5. The method of any claim 1 wherein said material exhibits at
least one glass to crystalline transformation onset in the range of
350.degree. C. to 675.degree. C., measured by DSC at a heating rate
of 10.degree. C./min.
6. The method of claim 1 wherein said material exhibits at least
one glass to crystalline transformation peak in the range of
350.degree. C. to 700.degree. C., measured by DSC at a heating rate
of 10.degree. C./min.
7. The method of claim 1 wherein said material exhibits at least
one melting onset at a temperature in the range of 1000.degree. C.
to 1250.degree. C., measured by DSC at a heating rate of 10.degree.
C./min.
8. The method of claim 1 wherein said material exhibits at least
one melting peak at a temperature in the range of 1000.degree. C.
to 1250.degree. C., measured by DSC at a heating rate of 10.degree.
C./min.
9. The method of any claim 1 wherein providing a glass forming
alloy comprising blending feedstocks and melting said feedstocks to
combine said feedstocks into said glass forming iron based metallic
alloy.
10. The method of any claim 1 wherein said material exhibits an
elasticity of up to 3%.
11. A metallic alloy material comprising: at least 35 at % iron;
nickel and/or cobalt present in the range of 7 at % to 50 at %; and
at least one element selected from the group consisting of boron,
carbon, silicon, phosphorous and nitrogen present in the range of 1
at % to 35 at %; wherein said atomic percent are selected to
provide 95 atomic percent for a given alloy and wherein said
material exhibits a strain of greater than 0.5%, a failure strength
in the range of 1 GPa to 5.9 GPa and a Vickers hardness (HV300) of
9 GPa to 15 GPa.
12. The alloy material of claim 11 wherein iron is present at 35 at
% to 92 at %.
13. The alloy material of claim 11 wherein said alloy comprises 45
at % to 70 at % iron, 10 at % to 30 at % Ni, 0 at % to 15 at %
cobalt, 7 at % to 25 at % B, 0 at % to 6 at % carbon and 0 at % to
2 at % silicon.
14. The alloy material of claim 11 wherein said alloy comprises 52
at % to 60 at % iron, 13 at % to 18 at % nickel, 8 at % to 12 at %
cobalt, 10 at % to 17 at % boron, 3 at % to 6 at % C and 0.3 at %
to 0.7 at % silicon.
15. The alloy material of claim 11 wherein said material exhibits
at least one glass to crystalline transformation onset in the range
of 350.degree. C. to 675.degree. C., measured by DSC at a heating
rate of 10.degree. C./min.
16. The alloy material of any claim 11 wherein said material
exhibits at least one glass to crystalline transformation peak in
the range of 350.degree. C. to 700.degree. C., measured by DSC at a
heating rate of 10.degree. C./min.
17. The alloy material of claim 11 wherein said material exhibits
at least one melting onset at a temperature in the range of
1000.degree. C. to 1250.degree. C., measured by DSC at a heating
rate of 10.degree. C./min.
18. The alloy material of claim 11 wherein said material exhibits
at least one melting peak at a temperature in the range of
1000.degree. C. to 1250.degree. C., measured by DSC at a heating
rate of 10.degree. C./min.
19. The alloy material of claim 11 wherein providing said alloy
material comprises blending feedstocks and melting said feedstocks
to combine said feedstocks into said metallic alloy.
20. The alloy material of claim 11 wherein said material exhibits
an elasticity of up to 3%.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/061,768 filed Jun. 16, 2008, the teachings of
which are incorporated by reference.
FIELD OF INVENTION
[0002] The present disclosure relates to iron based alloys, to
ductile metallic glasses that result in relatively high strength,
high elastic elongation, and high plastic elongation and to a
method for making same.
BACKGROUND
[0003] Metallic nanocrystalline materials and metallic glasses may
be considered to be special classes of materials known to exhibit
relatively high hardness and strength characteristics. Due to their
potential, they are considered to be candidates for structural
applications. However, these classes of materials may exhibit
limited fracture toughness associated with the rapid propagation of
shear bands and/or cracks, which may be a concern for the
technological utilization of these materials. While these materials
may show adequate ductility by testing in compression, when testing
in tension these materials may show elongations close to zero and
in the brittle regime. The inherent inability of these classes of
material to be able to deform in tension at room temperature may be
a limited factor for some potential structural applications where
intrinsic ductility is needed to avoid catastrophic failure.
[0004] In some cases, nanocrystalline materials may be understood
as polycrystalline structures with a mean grain size below 500 nm
including, in some cases, a mean grain size below 100 nm. Despite
their relatively attractive properties (high hardness, yield stress
and fracture strength), nanocrystalline materials may generally
show a disappointing and relatively low tensile elongation and mat
tend to fail in an extremely brittle manner. In fact, the decrease
of ductility for decreasing grain sizes has been known for a long
time as attested, for instance, by the empirical correlation
between the work hardening exponent and the grain size proposed by
others for cold rolled and conventionally recrystallized mild
steels. As the grain size progressively decreases, the formation of
dislocation pile-ups may become more difficult, limiting the
capacity for strain hardening, which may lead to mechanical
instability and cracking under loading.
SUMMARY
[0005] The present invention relates to a metallic alloy
comprising:
[0006] at least 35 atomic % iron, preferably 35 atomic % iron to 92
atomic % iron;
[0007] nickel and/or cobalt present in the range of 7 atomic % to
50 atomic %; and
[0008] at least one element selected from the group consisting of
boron, carbon, silicon, phosphorous and nitrogen present in the
range of 1 atomic % to 35 atomic %; wherein said atomic percents
are selected to provide 95 atomic percent for a given alloy.
[0009] According to another aspect the present invention relates to
a ductile metallic material made of an alloy as defined above being
a metallic glass, a nanocrystalline material or a mixture thereof
exhibiting at least one glass to crystalline transformation
measured by differential scanning calorimetry (DSC) at a heating
rate of 10.degree. C./min.
[0010] The metallic material of the present invention may exhibit
an elasticity of up to 3%, a strain of greater than 0.5%, a failure
strength in the range of 1 GPa to 5.9 GPa and a Vickers hardness
(HV300) of 9 GPa to 15 GPa.
[0011] According to a further aspect the present invention relates
to a method of forming a ductile metallic material comprising:
[0012] providing a glass forming iron based metallic alloy
comprising: at least 35 atomic % iron, preferably 35 atomic % iron
to 92 atomic % iron;
[0013] nickel and/or cobalt present in the range of 7 atomic % to
50 atomic %; and
[0014] at least one element selected from the group consisting of
boron, carbon, silicon, phosphorous and nitrogen present in the
range of 1 atomic % to 35 atomic %; wherein said atomic percent are
selected to provide 95 atomic percent for a given alloy;
[0015] melting said glass forming iron based metallic alloy;
[0016] forming said glass forming alloy and cooling said alloy at a
rate of 10.sup.2 to 10.sup.6 K/s obtaining a material comprising a
metallic glass, a nanocrystalline material or a mixture
thereof.
BRIEF DESCRIPTION OF DRAWINGS
[0017] The above-mentioned and other features of this disclosure,
and the manner of attaining them, may become more apparent and
better understood by reference to the following description of
embodiments described herein taken in conjunction with the
accompanying drawings, wherein:
[0018] FIGS. 1a through 1f illustrate DTA curves of the alloys
showing the presence of glass to crystalline transformation peak(s)
and melting peak(s); wherein FIG. 1a) illustrates Alloy 1 melt-spun
at 16 m/s, FIG. 1b) illustrates Alloy 4 melt-spun at 16 m/s, FIG.
1c) illustrates Alloy 2 melt-spun at 16 m/s, FIG. 1d) illustrates
Alloy 5 melt-spun at 16 m/s, FIG. 1e) illustrates ALLOY 3 melt-spun
at 16 m/s, and FIG. 1f) illustrates Alloy 6 melt-spun at 16
m/s.
[0019] FIGS. 2a through 2f illustrate DTA curves of the alloys
showing the presence of glass to crystalline transformation peak(s)
and melting peak(s); wherein FIG. 2a) illustrates Alloy 7 melt-spun
at 16 m/s, FIG. 2b) illustrates Alloy 10 melt-spun at 16 m/s, FIG.
2c) illustrates Alloy 8 melt-spun at 16 m/s, FIG. 2d) illustrates
Alloy 11 melt-spun at 16 m/s, FIG. 2e) illustrates ALLOY 9
melt-spun at 16 m/s, and FIG. 2f) illustrates Alloy 12 melt-spun at
16 m/s.
[0020] FIGS. 3a through 3f illustrate DTA curves of the alloys
showing the presence of glass to crystalline transformation peak(s)
and melting peak(s) (for 16 m/s samples); wherein FIG. 3a)
illustrates Alloy 13 melt-spun at 16 m/s, FIG. 3b) illustrates
Alloy 3 melt-spun at 10.5 m/s, FIG. 3c) illustrates Alloy 1
melt-spun at 16 m/s, FIG. 3d) illustrates Alloy 4 melt-spun at 10.5
m/s, FIG. 3e) illustrates ALLOY 2 melt-spun at 10.5 m/s, and FIG.
3f) illustrates Alloy 5 melt-spun at 10.5 m/s.
[0021] FIGS. 4a through 4f illustrate DTA curves of the alloys
showing the presence of glass to crystalline transformation
peak(s); wherein FIG. 4a) illustrates Alloy 6 melt-spun at 10.5
m/s, FIG. 4b) illustrates Alloy 9 melt-spun at 10.5 m/s, FIG. 4c)
illustrates Alloy 7 melt-spun at 10.5 m/s, FIG. 4d) illustrates
Alloy 10 melt-spun at 10.5 m/s, FIG. 4e) illustrates ALLOY 8
melt-spun at 10.5 m/s, and FIG. 4f) illustrates Alloy 11 melt-spun
at 10.5 m/s.
[0022] FIGS. 5a through 5b illustrates DTA curves of the alloys
showing the presence of glass to crystalline transformation
peak(s); FIG. 5a) illustrates Alloy 12 melt-spun at 10.5 m/s, and
FIG. 5b) illustrates Alloy 13 melt-spun at 10.5 m/s.
[0023] FIGS. 6a through 6c illustrate SEM backscattered electron
micrograph of the ALLOY 1 ribbon melt-spun at 16 m/s; wherein FIG.
6a) illustrates low magnification showing the entire ribbon cross
section, note the presence of isolated points of porosity, FIG. 6b)
illustrates medium magnification of the ribbon structure, and FIG.
6c) illustrates high magnification of the ribbon structure.
[0024] FIGS. 7a through 7c illustrate SEM backscattered electron
micrograph of the ALLOY 7 ribbon melt-spun at 16 m/s; wherein FIG.
7a) illustrates low magnification showing the entire ribbon cross
section, FIG. 7b) illustrates medium magnification of the ribbon
structure, note the presence of the free surface at the top of the
ribbon, and FIG. 7c) illustrates high magnification of the ribbon
structure.
[0025] FIGS. 8a through 8d illustrate SEM backscattered electron
micrograph of the ALLOY 11 ribbon; wherein FIG. 8a) illustrates low
magnification showing the entire ribbon cross section at 16 m/s,
FIG. 8b) illustrates high magnification of the ribbon structure at
16 m/s, note the presence of scratches and voids, FIG. 8c)
illustrates low magnification showing the entire ribbon cross
section at 10.5 m/s, note the presence of a Vickers hardness
indentation, and FIG. 8d) illustrates high magnification of the
ribbon structure at 10 m/s.
[0026] FIGS. 9a through 9b illustrate SEM backscattered electron
micrograph of the ALLOY 11 ribbon melt-spun at 16 m/s and then
annealed at 1000.degree. C. for 1 hour; wherein FIG. 9a)
illustrates medium magnification of the ribbon structure, and FIG.
9b) illustrates high magnification of the ribbon structure.
[0027] FIGS. 10a through 10d illustrate SEM secondary electron
micrograph and EDS scans of the ALLOY 11 ribbon melt-spun at 16
m/s; wherein FIG. 10a) illustrates high magnification secondary
electron picture of the ribbon structure, FIG. 10b) illustrates EDS
map showing the presence of iron, FIG. 10c) illustrates EDS map
showing the presence of nickel, and FIG. 10d) illustrates EDS map
showing the presence of cobalt.
[0028] FIGS. 11a and 11b illustrate the two point bend test system;
wherein FIG. 11a) is a picture of bend tester, and FIG. 11b)
illustrates a close-up schematic of bending process.
[0029] FIG. 12 illustrates bend test data showing the cumulative
failure probability as a function of failure strain for the ALLOY
1A series alloys melt-spun at 16 m/s.
[0030] FIG. 13 illustrates bend test data showing the cumulative
failure probability as a function of failure strain for the ALLOY
1B series alloys melt-spun at 16 m/s.
[0031] FIG. 14 illustrates bend test data showing the cumulative
failure probability as a function of failure strain for the ALLOY
1C series alloys melt-spun at 16 m/s.
[0032] FIG. 15 illustrates bend test data showing the cumulative
failure probability as a function of failure strain for the ALLOY
1A series alloys melt-spun at 10.5 m/s.
[0033] FIG. 16 illustrates bend test data showing the cumulative
failure probability as a function of failure strain for the ALLOY
1B series alloys melt-spun at 10.5 m/s.
[0034] FIG. 17 illustrates bend test data showing the cumulative
failure probability as a function of failure strain for the ALLOY
1C series alloys melt-spun at 10.5 m/s.
[0035] FIG. 18 illustrates DTA curves of the ALLOY 11 alloys
melt-spun at a wheel tangential velocity of 16 m/s, 10.5 m/s and 5
m/s.
[0036] FIG. 19 illustrates bend test data showing the cumulative
failure probability as a function of failure strain for the ALLOY
11 series alloys melt-spun at 16 m/s and annealed at 450.degree. C.
for 3 hour.
[0037] FIG. 20 illustrates examples of ALLOY 11 ribbon samples
which have been bent 180.degree. during two point bending without
breaking.
[0038] FIG. 21 illustrates an example of a ALLOY 11 ribbon sample
bent .about.2.5% strain with a kink appearing (see arrow)
indicating the onset of plastic deformation.
DETAILED DESCRIPTION
[0039] The present application relates to glass forming iron based
alloys, which, when formed, may include metallic glass or a mixed
structure consisting of metallic glass and nanocrystalline phases.
Such alloys may exhibit relatively high strain up to 97% and
relatively high strength up to 5.9 GPa. In addition, relatively
high elasticity of up to 2.6% has been observed, which may be
consistent with the amorphous structure. Thus, the alloys exhibit
structures and properties which may yield relatively high
elasticity similar to a metallic glass, high plasticity similar to
a ductile crystalline metal, and relatively high strength as
observed in nanoscale materials.
[0040] Metallic glass materials or amorphous metal alloys may
exhibit relatively little to no long range order on a scale of a
few atoms, such as ordering in the range of 100 nm or less. It may
be appreciated that local ordering may be present. Nanocrystalline
materials may be understood herein as polycrystalline structures
with a mean grain size below 500 nm including all values and
increments in the range of 1 nm to 500 nm, such as less than 100
nm. It may be appreciated that to some degree, the characterization
of amorphous and nanocrystalline material may overlap and crystal
size in a nanocrystalline material may be smaller than the size of
short range order in an amorphous composition. These materials are
characterized in that they exhibit at least one glass to
crystalline transformation measured by differential scanning
calorimetry (DSC) at a heating rate of 10.degree. C./min.
[0041] The iron based alloys contemplated herein may include at
least 35 atomic percent (at %) iron, nickel and/or cobalt in the
range of 7 to 50 at %, and at least one non/metal or metalloid
selected from the group consisting of boron, carbon, silicon,
phosphorus, or nitrogen present in the range of 1 to 35 at %. The
atomic percents may then be selected and configured to provide at
least 95 atomic percent for a given alloy, the balance to 100
atomic percent being impurities. For example, one may have nickel
or cobalt at 7 at % and one of boron, carbon, silicon, phosphorous
or nitrogen at 1 at %, the balance iron at 92 at %. In this case
there would be no impurities. By way of further example, one may
have nickel or cobalt at 7 at % and one of boron, carbon, silicon,
phosphorous or nitrogen at 1 at %, the balance iron at 87 at %, the
balance being impurities of up to 5 atomic percent.
[0042] Therefore, it should be clear that within each of these
general ranges of atomic percent for each of the metals one may
utilize preferred sub-ranges. For example, in the case of iron, the
lower limit of the range may be independently selected from 35, 36,
37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53,
54 or 55 at %, whereas the upper limit of the range may be
independently selected from 92, 91, 90, 89, 88, 87, 86, 85, 84, 83,
82, 81, 80, 79, 78, 77, 76, 75, 74, 73, 72, 71, 70, 69, 68, 67, 66,
65, 64, 63, 62, 61, 60, 59, 58, 57 or 56 at %. Suitable ranges for
iron in the alloys according to the present invention may be 45
atomic % to 70 atomic %, or 50 atomic % to 65 atomic % or 52 atomic
% to 60 atomic %.
[0043] For the second group of ingredients selected from nickel
and/or cobalt, the lower limit of the range may be independently
selected from 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
21, 22, 23, 24, 25 or 26 at %, whereas the upper limit of the range
may be independently selected from 50, 49, 48, 47, 46, 45, 44, 43,
42, 41, 40, 39, 38, 37, 36, 35, 34, 33, 32, 31, 30, 29, or 28 at %.
The alloy of the present invention may contain either nickel or
cobalt in amounts within the above specified ranges or a
combination of both. For example the alloy of the present invention
may contain 10 to 40 at % Ni, whereby the lower limit of the range
may be independently selected from 10, 11, 12, 13, 14, 15 or 16 at
%, whereas the upper limit of the range may be independently
selected from 40, 39, 39, 37, 36, 35, 34, 33, 32, 31, 30, 29, 28,
27, 26, 25, 24, 23, 22, 21, 20, 19 or 18 at %, possibly in
combination with cobalt in an amount of 0 to 20, whereby the lower
limit of the range may be independently selected from 0, 1, 2, 3,
4, 5, 6, 7, 8, 9 or 10 whereas the upper limit may be independently
selected from 20, 19, 18, 17, 16, 15, 14, 13, 12 or 11. Suitable
ranges for nickel are 10 to 30 at % or 13 to 18 at %. Suitable
ranges for cobalt are 0 to 15 at % or 8 to 12 at %.
[0044] For the third group of ingredients the non/metal or
metalloid selected from the group consisting of boron, carbon,
silicon, phosphorous or nitrogen, the lower limit of the range may
be independently selected from 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
12, 13, 14, 15, 16, 17, 18 at %, whereas the upper limit of the
range may be independently selected from 35, 34, 33, 32, 31, 30,
29, 28, 27, 26, 25, 24, 23, 22, 21, 20 or 19 at %.
[0045] In some examples, the alloys contemplated herein may include
even more preferred sub-ranges of the above mentioned general
ranges such as 45 at % to 70 at % iron. A particular preferred
sub-range of nickel may be 10 at % to 30 at % nickel. A particular
preferred sub-range of cobalt may be 0 at % to 15 at % cobalt. A
particularly preferred sub-range of boron may be 7 at % to 25 at %
boron. A particular preferred sub-range of carbon may be 0 at % to
6 at %. A particular preferred sub-range of silicon may be 0 at %
to 2 at %. It is to be pointed out that according to present
invention any of the ranges for a particular component of the alloy
of the present invention may be combined with any range of any
other component as described herein.
[0046] For example, one particularly preferred sub-range for the
disclosed alloy may provide alloys having in the range of 52 at %
to 60 at % iron, 13 at % to 18 at % nickel, 8 at % to 12 at %
cobalt, 10 at % to 17 at % boron, 3 at % to 6 at % carbon, and 0.3
at % to 0.7 at % silicon.
[0047] The glass forming iron based alloys may exhibit a general
range for the critical cooling rate for metallic glass formation of
10.sup.2 to 10.sup.6 K/second (K/s). More preferably, the critical
cooling rate may be 100,000 K/s or less, including all values and
increments therein such as 10,000 K/s to 1,000 K/s, etc. The
resulting structure of the alloy material may consist primarily of
metallic glass and/or crystalline nanostructural features less than
500 nm in size. In some examples, the metallic glass and/or
nanocrystalline alloy, the alloy may be at least 10% by volume
metallic glass, including all values and increments in the range of
10% to 80% by volume metallic glass.
[0048] The iron based alloy may exhibit an elastic elongation
greater than 0.5%, including all values and increments in the range
of 0.5% to 3.0%. Elastic elongation may be understood as, a change
in length of a material upon application of a load which may be
substantially recoverable. In addition, the iron based alloy may
exhibit a tensile or bending elongation greater than 0.6%, such as
in the range of 0.6% and up to 97%, including all values and
increments therein. Tensile or bending elongation may be understood
as an increase in length of sample resulting from the application
of a load in tension or bending. Furthermore, the iron based alloy
may exhibit strength greater than 1 GPa, including all values and
increments in the range of 1 GPa to 5.9 GPa. Strength may be
understood as the stress required to break, rupture, or cause
failure to the material. It may be appreciated that the alloy may
exhibit a combination of properties with a strength greater than 1
GPa and a tensile or bending elongation greater than 2%. The formed
iron based alloys may also exhibit a hardness (VH.sub.300) in the
range of 10 GPa to 15 GPa, including all values and increments
therein.
[0049] The alloys may be prepared by providing feedstock materials
at the desired proportions. The feedstock materials may then be
melted, such as by arc-melting system or by induction heating,
producing a glass forming metal alloy. The glass forming metal
alloy may then be formed under a shielding gas, using an inert gas
such as argon, into ingots. The formed alloys may be flipped and
remelted a number of times to ensure homogeneity of the glass
forming metal alloy. The glass forming metal alloy may be further
cast or formed into a desired shape. In some examples, the glass
forming metal alloys may be melting and then cast on or between one
or more copper wheel, forming ribbons or a sheet or film of the
alloy composition. In other examples, the glass forming alloy may
be fed as a wire or rod into a thermal spray processes, such as
HVOF, plasma arc, etc. The final forming process may provide a
cooling rate of less than 100,000 K/s.
[0050] In some embodiments, the formed alloys may exhibit no
grains, phases or crystalline structures, or other long term
ordering on the scale of 100 nm or greater, including all values
and increments in the range of 100 nm to 1,000 nm. The formed alloy
compositions may also exhibit a glass to crystalline transformation
onset in the range of 350.degree. C. to 675.degree. C., when
measured by DSC at a heating rate of 10.degree. C./min., including
all values and increments therein. The formed alloy compositions
may exhibit a glass to crystalline transformation peak in the range
of 350.degree. C. to 700.degree. C., when measured by DSC at a
heating rate of 10.degree. C./min., including all values and
increments therein. Furthermore, the formed alloys may exhibit a
melting onset in the range of 1000.degree. C. to 1250.degree. C.,
when measured by DSC at a heating rate of 10.degree. C./min,
including all values and increments therein. The formed alloys may
also exhibit a melting peak in the range of 1000.degree. C. to
1250.degree. C., including all values and increments therein. It
may be appreciated that the alloys may, in some examples, exhibit
at least one and possibly up to three glass to crystalline
transformations and/or at least one and possibly up to three
melting transitions. In addition, the formed alloys may exhibit a
density in the range of 7.3 g/cm.sup.3 to 7.9 g/cm.sup.3.
EXAMPLES
[0051] The following examples are presented for the purposes of
illustration only and, therefore, are not meant to limit the
description provided herein or claims appended hereto.
Sample Preparation
[0052] Relatively high purity elements, having a purity of at least
99 at %, were used to prepare 15 g alloy feedstocks of the ALLOY 1
series alloys. The ALLOY 1 series alloy feedstocks were weighed out
according to the atomic ratio's provided in Table 1. Each feedstock
material was then placed into the copper hearth of an arc-melting
system. The feedstock was arc-melted into an ingot using high
purity argon as a shielding gas. The ingots were flipped several
times and remelted to ensure homogeneity. After mixing, the ingots
were then cast in the form of a finger approximately 12 mm wide by
30 mm long and 8 mm thick. The resulting fingers were then placed
in a melt-spinning chamber in a quartz crucible with a hole
diameter of .about.0.81 mm. The ingots were melted in a 1/3 atm
helium atmosphere using RF induction and then ejected onto a 245 mm
diameter copper wheel which was traveling at tangential velocities
which varied from 5 to 25 m/s. The resulting ALLOY 1 series ribbon
that was produced had widths which were typically .about.1.25 mm
and thickness from 0.02 to 0.15 mm.
TABLE-US-00001 TABLE 1 Atomic Ratio's for ALLOY 1 Series Elements
Class A Class B Class C Fe Ni Co B C Si ALLOY 1 56.00 15.50 10.00
13.20 4.80 0.50 ALLOY 2 56.00 13.07 8.43 16.05 5.84 0.61 ALLOY 3
56.00 14.28 9.22 14.63 5.32 0.55 ALLOY 4 56.00 16.72 10.78 11.77
4.28 0.45 ALLOY 5 56.00 17.93 11.57 10.35 3.76 0.39 ALLOY 6 60.00
15.50 10.00 10.35 3.76 0.39 ALLOY 7 58.00 15.50 10.00 11.77 4.28
0.45 ALLOY 8 54.00 15.50 10.00 14.63 5.32 0.55 ALLOY 9 52.00 15.50
10.00 16.05 5.84 0.61 ALLOY 10 52.00 17.93 11.57 13.20 4.80 0.50
ALLOY 11 54.00 16.72 10.78 13.20 4.80 0.50 ALLOY 12 58.00 14.28
9.22 13.20 4.80 0.50 ALLOY 13 60.00 13.07 8.43 13.20 4.80 0.50
Cooling Rates
[0053] Expanding upon the above, it may therefore be appreciated
that after melt-spinning, long continuous ribbons are produced
which are dimensionally thin in one direction (i.e. the thickness).
The thickness of the ribbons that were produced were measured using
a micrometer. In Table 1A, the typical ribbon thickness range for
the alloys in Table 1 as a function of wheel tangential velocity is
shown. Based on the thickness, the cooling rate can be estimated
using the well known relation dT/dt=10/(dc).sup.2. In Table 1A, the
estimated cooling rate range is shown for each ribbon thickness. As
shown, the cooling rate range available in melt-spinning using
normal parameters ranges from 2.5*10.sup.6 to 16*10.sup.3 K/s.
Preferred cooling rates based on the known ductility range is in
the range of 10.sup.3 to 10.sup.6 K/s.
TABLE-US-00002 TABLE 1A Thickness/Cooling Rate Dependence Wheel
Ribbon Speed Thickness Cooling Rate K/s (m/s) (.mu.m) Thin Thick 39
20-25 2,500,000 1,600,000 30 30-40 1,111,111 625,000 16 60-70
277,778 204,082 10.5 70-80 204,082 156,250 7.5 120-140 69,444
51,020 5 180-250 30,864 16,000
[0054] It should also be noted that the cooling rate dependency to
obtain a glass-like or nanocrystalline morphology may depend on the
precise composition of a given alloy and may therefore be
determined for a given alloy composition. For example, this may be
accomplished by measuring the glass-crystalline transition by DSC
as noted herein.
Density
[0055] The density of the alloys in ingot form was measured using
the Archimedes method in a balance allowing for weighing in both
air and distilled water. The density of the arc-melted 15 gram
ingots for each alloy is tabulated in Table 2 and was found to vary
from 7.39 g/cm.sup.3 to 7.85 g/cm.sup.3. Experimental results have
revealed that the accuracy of this technique is +-0.01
g/cm.sup.3.
TABLE-US-00003 TABLE 2 Density of Alloys Alloy Density (g/cm.sup.3)
ALLOY 1 7.75 ALLOY 2 7.39 ALLOY 3 7.70 ALLOY 4 7.82 ALLOY 5 7.85
ALLOY 6 7.83 ALLOY 7 7.81 ALLOY 8 7.72 ALLOY 9 7.69 ALLOY 10 7.79
ALLOY 11 7.77 ALLOY 12 7.74 ALLOY 13 7.73
As-Solidified Structure
[0056] Thermal analysis was performed on the as-solidified ribbon
structure on a Perkin Elmer DTA-7 system with the DSC-7 option.
Differential thermal analysis (DTA) and differential scanning
calorimetry (DSC) was performed at a heating rate of 10.degree.
C./minute with samples protected from oxidation through the use of
flowing ultrahigh purity argon. In Table 3, the DSC data related to
the glass to crystalline transformation is shown for the ALLOY 1
series alloys that have been melt-spun at two different wheel
tangential velocities at 16 m/s and 10.5 m/s. Note that the cooling
rate increases at increasing wheel tangential velocities. Typical
ribbon thickness's for the alloys melt-spun at 16 m/s and 10.5 m/s
are 0.04 to 0.05 mm and 0.06 to 0.08 mm respectively. In FIG. 1
through 5, the corresponding DTA plots are shown for each ALLOY 1
series sample melt-spun at 16 and 10.5 m/s. As can be seen, the
majority of samples (all but two) exhibit glass to crystalline
transformations verifying that the as-spun state contains
significant fractions of metallic glass. The glass to crystalline
transformation occurs in either one stage, two stage, or three
stages in the range of temperature from .about.350 to
.about.700.degree. C. and with enthalpies of transformation from
.about.-1 to .about.-125 J/g.
TABLE-US-00004 TABLE 3 DSC Data for Glass To Crystalline
Transformations Peak #1 Peak #1 Peak #2 Peak #2 Peak #3 Peak #3
Onset Peak .DELTA.H Onset Peak .DELTA.H Onset Peak .DELTA.H Alloy
Glass (.degree. C.) (.degree. C.) (-J/g) (.degree. C.) (.degree.
C.) (-J/g) (.degree. C.) (.degree. C.) (-J/g) ALLOY 1w16 Yes 430
442 35.9 478 483 58.1 ALLOY 1w10.5 Yes 440 453 34.1 477 484 56.2
ALLOY 2w16 Yes 474 477 66.2 ALLOY 2w10.5 Yes 473 478 100.7 ALLOY
3w16 Yes 464 469 71.7 ALLOY 3w10.5 Yes 466 471 90.5 ALLOY 4w16 Yes
390 411 5.8 471 477 13.3 ALLOY 4w10.5 Yes 468 476 17.8 ALLOY 5w16
Yes 465 473 3.4 ALLOY 5w10.5 No ALLOY 6w16 Yes 473 478 22.8 ALLOY
6w10.5 No ALLOY 7w16 Yes 411 426 * 431 435 19.9 478 483 21.7 ALLOY
7w10.5 Yes 358 405 64.6 474 480 60.1 ALLOY 8w16 Yes 437 450 22.8
477 483 44.4 665 683 3.3 ALLOY 8w10.5 Yes 463 469 119.0 ALLOY 9w16
Yes 428 439 1.5 471 474 35.7 669 678 4.9 ALLOY 9w10.5 Yes 469 474
49.0 ALLOY 10w16 Yes 460 468 121.8 477 483 * ALLOY 10w10.5 Yes 374
390 5.8 437 450 46.6 471 476 ~76.5 ALLOY 11w16 Yes 439 449 13.0 475
480 24.6 ALLOY 11w10.5 Yes 437 447 30.6 475 480 53.8 ALLOY 12w16
Yes 432 450 34.2 481 486 35.4 ALLOY 12w10.5 Yes 442 453 43.1 481
486 70.4 ALLOY 13w16 Yes 444 457 12.4 484 491 17.7 ALLOY 13w10.5
Yes 447 460 50.2 482 489 46.5 * Overlapping peaks, peak 1 and peak
2 enthalpy combined
[0057] In Table 4, elevated temperature DTA results are shown
indicating the melting behavior for the ALLOY 1 series alloys. As
can be seen in Table 4 and FIGS. 1 through 3, the melting occurs in
1 to 3 stages with initial melting (i.e. solidus) observed from
.about.1060.degree. C. to .about.1100.degree. C. with final melting
up to .about.1130.degree. C.
TABLE-US-00005 TABLE 4 Differential Thermal Analysis Data for
Melting Behavior Peak #1 Peak #1 Peak #2 Peak #2 Peak #3 Peak #3
Alloy Onset (.degree. C.) Peak (.degree. C.) Onset (.degree. C.)
Peak (.degree. C.) Onset (.degree. C.) Peak (.degree. C.) ALLOY
1w16 1078 1088 1089 1095 ALLOY 2w16 1071 1085 1115 1129 ALLOY 3w16
1077 1087 1089 1096 ALLOY 4w16 1099 1087 1086 1091 ALLOY 5w16 1079
1090 1084 1092 1080 1095 ALLOY 6w16 1085 1094 1094 1102 ALLOY 7w16
1083 1090 1093 1098 ALLOY 8w16 1075 1087 1082 1092 1087 1098 ALLOY
9w16 1064 1074 1070 1076 1108 1119 ALLOY 10w16 1078 1095 1089 1100
ALLOY 11w16 1075 1083 1080 1088 1086 1094 ALLOY 11w5 1076 1090 1088
1098 ALLOY 12w16 1081 1098 ALLOY 13w16 1085 1093
SEM Microscopy Studies
[0058] To further examine the ribbon structure, scanning electron
microscopy (SEM) was done on selected ribbon samples. Melt spun
ribbons were mounted in a standard metallographic mount with
several ribbons held using a metallography binder clip. The binder
clip containing the ribbons was set into a mold and an epoxy is
poured in and allowed to harden. The resulting metallographic mount
was ground and polished using appropriate media following standard
metallographic practices. The structure of the samples was observed
using an EVO-60 scanning electron microscope manufactured by Carl
Zeiss SMT Inc. Typical operating conditions were electron beam
energy of 17.5 kV, filament current of 2.4 A, and spot size setting
of 800. Energy Dispersive Spectroscopy was conducted with an Apollo
silicon drift detector (SDD-10) using Genesis software both of
which are from EDAX. The amplifier time was set to 6.4 micro-sec so
that the detector dead time was about 12-15%.
[0059] In FIG. 6, SEM backscattered electron micrograph are shown
of the ALLOY 1 ribbon melt-spun at 16 m/s. As can be seen, while
isolated points of porosity are found, no crystalline structural
features were observed. In FIG. 7, SEM backscattered electron
micrographs of the ALLOY 7 ribbons melt-spun at 16 m/s are shown.
Consistent with the ALLOY 1 results low, medium, and high
magnification images do not reveal any grains, phases, or
crystalline structure. In FIG. 8, SEM backscattered electron
micrograph of the ALLOY 11 ribbon are shown comparing the 16 m/s
sample to the 10.5 m/s samples. Note that no crystalline structure
is found on the scale of the resolution limit of the SEM and no
differences between the two cooling rates were observed. In FIG. 9,
SEM backscattered electron micrograph of the ALLOY 11 ribbon
melt-spun at 16 m/s and then annealed at 1000.degree. C. for 1 hour
are shown at two different magnifications. Note that even after
this very high temperature heat treatment, no grains, phases, or
crystalline material was found.
[0060] From the DTA results, it is relatively clear that a heat
treatment at this temperature would certainly lead to full
devitrification so the results indicate that the grains/phases that
are formed are very stable against coarsening. In FIG. 10a, a high
magnification secondary electron micrograph is shown of the ALLOY
11 ribbon melt-spun at 16 m/s. Energy dispersive spectroscopy (EDS)
maps were taken at low (1,770.times.), medium (5,000.times.), and
high magnification (20,000.times.). In FIGS. 10b, 10c, and 10d;
high magnification EDS maps of iron, nickel, and cobalt
respectively are shown corresponding to the region shown in FIG.
10a. As can be seen, a uniform distribution of iron, nickel, and
cobalt are found consistent with the lack of phases found. Note
that the speckled morphology of the pictures is not due to chemical
segregation but is an artifact of the EDS scanning resolution.
Mechanical Property Testing
[0061] Mechanical property testing was performed primarily through
using nanoindentor testing to measure Young's modulus and bend
testing to measure breaking strength and elongation. The following
sections detail the technical approach and measured data.
Nano-indentation Testing
[0062] Nano-indentation uses an established method where an
indenter tip with a known geometry is driven into a specific site
of the material to be tested, by applying an increasing normal
load. After reaching a pre-set maximum value, the normal load is
reduced until partial or complete relaxation occurs. This procedure
is performed repetitively; at each stage of the experiment and the
position of the indenter relative to the sample surface is
precisely monitored with a differential capacitive sensor. For each
loading/unloading cycle, the applied load value is plotted with
respect to the corresponding position of the indenter. The
resulting load/displacement curves provide data specific to the
mechanical nature of the material under examination. Calculation of
the Young's Modulus is done by first calculating the reduced
modulus (see Equation #1), E.sub.r and then using that value to
calculate Young's Modulus (see Equation #2).
E r = .pi. 2 S A c = .pi. 2 1 C 1 A c Equation #1 ##EQU00001##
which can be calculated having derived S and A.sub.C from the
indentation curve using the area function, A.sub.C being the
projected contact area.
1 E r = 1 - v 2 E + 1 - v i 2 E i Equation #2 ##EQU00002##
where E.sub.i and v.sub.i are the Young's modulus and Poisson
coefficient of the indenter and v the Poisson coefficient of the
tested sample.
[0063] The test conditions shown in Table 5 were used for the
nano-indentation measurements. The measured values of Hardness and
Young's modulus for the samples as well as the penetration depth
(.DELTA.d) are tabulated in Tables 6 through 10 with their averages
and standard deviations. As shown, the hardness was found to be
very high and ranged from 960 to 1410 kg/mm.sup.2 (10.3 to 14.9
GPa). The elastic modulus (i.e. Young's Modulus) was found to vary
from 119 to 134 GPa. Since all ALLOY 1 series alloys were not
measured using nanoindentation, the Young's modulus was estimated
for the remaining alloys to be within the existing range and 125
GPa was used for bend testing calculations of strength.
TABLE-US-00006 TABLE 5 Parameters Used For Nanoindentation Maximum
force (mN) 300 Maximum depth (nm) N/A Loading rate (mN/min) 600
Unloading rate (mN/min) 600 Pause (s) 0 Computation Method Oliver
& Pharr Indenter type Berkovich
TABLE-US-00007 TABLE 6 Nanoindentation Test Results for ALLOY 11
Ribbon at 16 m/s Hv H E .DELTA.d [Vickers] [GPa] [GPa] [.mu.m] 1
1108.49 11.73 133.61 1.34 2 969.52 10.26 117.63 1.43 3 1061.97
11.24 126.80 1.37 4 1026.85 10.87 123.27 1.39 5 1012.81 10.72
123.04 1.40 Average 1035.93 10.96 124.87 1.39 Std dev 46.84 0.50
5.26 0.03
TABLE-US-00008 TABLE 7 Nanoindentation Test Results for ALLOY 1
Ribbon at 16 m/s Hv H E .DELTA.d [Vickers] [GPa] [GPa] [.mu.m] 1
1083.37 11.46 127.75 1.36 2 1082.66 11.46 127.13 1.36 3 1084.57
11.48 128.43 1.36 4 1103.14 11.67 129.74 1.35 5 1081.20 11.44
131.45 1.36 Average 1087.11 11.50 128.90 1.36 Std dev 8.10 0.08
1.54 0.004
TABLE-US-00009 TABLE 8 Nanoindentation Test Results for ALLOY 7
Ribbon at 16 m/s Hv H E .DELTA.d [Vickers] [GPa] [GPa] [.mu.m] 1
1261.18 13.35 129.14 1.31 2 1409.36 14.91 141.64 1.25 3 1398.76
14.80 133.46 1.27 4 1322.84 14.00 138.57 1.27 5 1203.07 12.73
127.86 1.33 Average 1319.04 13.96 134.13 1.29 Std dev 79.15 0.84
5.31 0.029
TABLE-US-00010 TABLE 9 Nanoindentation Test Results for ALLOY 3
Ribbon at 16 m/s Hv H E .DELTA.d [Vickers] [GPa] [GPa] [.mu.m] 1
1035.74 10.96 118.44 1.40 2 1047.94 11.09 118.20 1.40 3 1047.08
11.08 117.97 1.40 4 1048.99 11.10 118.29 1.40 5 1074.18 11.37
120.58 1.38 Average 1050.79 11.12 118.70 1.40 Std dev 12.64 0.13
0.95 0.01
TABLE-US-00011 TABLE 10 Nanoindentation Test Results for ALLOY 11
Ribbon at 5 m/s Hv H E .DELTA.d [Vickers] [GPa] [GPa] [.mu.m] 1
968.91 10.25 129.87 1.40 2 975.18 10.32 130.02 1.40 3 958.18 10.14
128.19 1.41 4 1028.37 10.88 137.00 1.36 5 1098.01 11.62 140.01 1.33
Average 1005.73 10.64 133.02 1.38 Std dev 52.11 0.55 4.62 0.03
Two-Point Bend Testing
[0064] The two-point bending method for strength measurement was
developed for thin, highly flexible specimens, such as optical
fibers and ribbons. The method involves bending a length of tape
(fiber, ribbon, etc.) into a "U" shape and inserting it between two
flat and parallel faceplates. One faceplate is stationary while the
second is moved by a computer controlled stepper motor so that the
gap between the faceplates may be controlled to a precision of
better than .about.5 .mu.m with an .about.10 .mu.m systematic
uncertainty due to the zero separation position of the faceplates
(FIG. 1). The stepper motor moves the faceplates together at a
precisely controlled specified speed at any speed up to 10,000
.mu.m/s. Fracture of the tape is detected using an acoustic sensor
which stops the stepper motor. Since for measurements on the tapes,
the faceplate separation at failure varied between 2 and 11 mm, the
precision of the equipment does not influence the results.
[0065] The strength of the specimens may be calculated from the
faceplate separation at failure. The faceplates constrain the tape
to a particular deformation so that the measurement directly gives
the strain to failure. The Young's modulus of the material is used
to calculate the failure stress according to the following formulas
(Equation #3):
f = 1.198 ( d D - d ) .sigma. f = 1.198 E ( d D - d )
##EQU00003##
where d is the tape thickness and D is the faceplate separation at
failure. Young's modulus was measured from nanoindentation testing
and was found to vary from 119 to 134 GPa for the ALLOY 1 series
alloys. As indicated earlier, for the samples not measured Young's
Modulus was estimated to be 125 GPa. The shape of the tape between
the faceplates is an elastica which is similar to an ellipse with
an aspect ratio of .about.2:1. The equation assumes elastic
deformation of the tape. When tapes shatter on failure and the
broken ends do not show any permanent deformation, there is not
extensive plastic deformation at the failure site and so the
equations are accurate. Note that even if plastic deformation
occurs as shown in a number of the ALLOY 1 series alloys, the
bending measurements would still provide a relative measure of
strength. The strength data for materials is typically fitted to a
Weibull distribution as shown in Equation #4:
P f = 1 - exp { - ( 0 ) m } ##EQU00004##
where m is the Weibull modulus (an inverse measure of distribution
width) and .epsilon..sub.0 is the Weibull scale parameter (a
measure of centrality, actually the 63% failure probability). In
general, m is a dimensionless number corresponding to the
variability in measured strength and reflects the distribution of
flaws. This distribution is widely used because it is simple to
incorporate Weibull' s weakest link theory which describes how the
strength of specimens depends on their size.
[0066] In FIGS. 12, 13, and 14, two point bend results are shown
giving the cumulative failure probability as a function of failure
strain for the ALLOY 1A series, ALLOY 1B series, and ALLOY 1C
alloys respectively, which were melt-spun at 16 m/s. Note that
every data point in these Figures represents a separate bend test
and for each sample, 17 to 25 measurements were done. In Table 11,
the results on these 16 m/s bend test measurements are tabulated
including Young's Modulus (GPA and psi), failure strength (GPA and
psi), Weibull Modulus, average strain (%), and maximum strain (%).
Note that for the ALLOY 7 sample that all ribbons tested did not
break during the test so failure strength could not be measured.
The Young's Modulus calculation and estimation was described in the
previous nanoindentation testing section. The failure strength
calculated according to Equation #3 is found to be relatively high
and ranges from 2.24 to 5.88 GPa (325,000 to 855,000 psi). The
Weibull Modulus was found to vary from 2.43 to 10.1 indicating the
presence of macrodefects in some of the ribbons causing premature
failure. The average strain in percent was calculated based on the
sample set that broke during two-point bend testing. The average
strain ranged from 1.37 to 97%, in the case of the ALLOY 7 sample
that did not break during the testing. The maximum strain in
percent was the maximum strain found during bending for the samples
that broke or 97% for the samples that did not break during
testing. The maximum strain was found to vary from 3.4% to 97%.
TABLE-US-00012 TABLE 11 Results of Bend Testing on Thin Ribbons (16
m/s) Youngs Failure Youngs Failure Avg Max Modulus Strength Modulus
Strength Weibull Strain Strain Alloy (GPa) (GPa) (psi) (psi)
Modulus (%)** (%) ALLOY 1 128.9 2.42 18,695,360 350,991 4.60 1.95
97 ALLOY 2 125* 3.80 18,129,713 551,143 2.43 2.03 97 ALLOY 3 118.7
2.84 17,215,975 411,907 6.01 1.97 97 ALLOY 4 125* 3.22 18,129,713
467,021 4.98 2.00 97 ALLOY 5 125* 3.03 18,129,713 439,464 2.98 1.27
3.4 ALLOY 6 125* 5.88 18,129,713 852,822 3.97 2.82 4.7 ALLOY 7
134.1 -- 19,452,891 -- -- 97 97 ALLOY 8 125* 2.24 18,129,713
324,884 5.99 1.37 97 ALLOY 9 125* 4.73 18,129,713 686,028 5.77 2.48
3.78 ALLOY 10 125* 2.68 18,129,713 388,701 6.93 1.74 97 ALLOY 11
133.0 2.67 19,292,915 385,800 10.1 1.87 97 ALLOY 12 125* 3.33
18,129,713 482,976 7.21 2.16 97 ALLOY 13 125* 3.76 18,129,713
545,342 4.81 2.15 18.2 *assumed value **for samples that broke
during bend testing
[0067] In FIGS. 15, 16, and 17, two point bend results are shown
giving the cumulative failure probability as a function of failure
strain for the ALLOY 1A series, ALLOY 1B series, and ALLOY 1C
alloys respectively which have been melt-spun at 10.5 m/s. Note
that every data point in these Figures represents a separate bend
test and for each sample, 17 to 25 measurements were done. In Table
12, the results on these 10.5 m/s bend test measurements are
tabulated including Young's Modulus (GPA and psi), failure strength
(GPA and psi), Weibull Modulus, average strain (%), and maximum
strain (%). The Young's Modulus calculation and estimation was
described in the previous nanoindentation testing section. The
failure strength calculated according to Equation #3 is found to be
very high and ranges from 1.08 to 5.36 GPa (160,000 to 780,000
psi). The Weibull Modulus was found to vary from 2.42 to 6.24
indicating the presence of macrodefects in some of the ribbons
causing premature failure. The average strain in percent ranged
from 0.63 to 2.25% and the maximum strain in percent was found to
vary from 0.86% to 4.00%.
TABLE-US-00013 TABLE 12 Results of Bend Testing on Thick Ribbons
(10.5 m/s) Youngs Failure Youngs Failure Avg Max Modulus Strength
Modulus Strength Weibull Strain Strain Alloy (GPa) (GPa) (psi)
(psi) Modulus (%)** (%) ALLOY 1 128.9 2.64 18,695,360 382,900 3.76
1.26 2.05 ALLOY 2 125* 1.08 18,129,712 156,641 5.51 0.63 0.86 ALLOY
3 118.7 2.31 17,215,975 335,037 4.04 1.11 1.85 ALLOY 4 125* 4.13
18,129,712 599,006 3.22 1.75 3.30 ALLOY 5 125* 2.96 18,129,712
429,312 4.00 1.64 2.37 ALLOY 6 125* 4.16 18,129,712 603,357 2.35
1.85 3.33 ALLOY 7 134.1 5.36 19,449,556 777,402 3.09 2.25 4.00
ALLOY 8 125* 2.99 18,129,712 433,663 4.12 1.52 2.39 ALLOY 9 125*
2.17 18,129,712 314,732 2.42 1.43 1.73 ALLOY 10 125* 2.98
18,129,712 432,212 4.84 1.73 2.38 ALLOY 11 133.0 2.66 19,290,014
385,800 3.28 1.80 3.21 ALLOY 12 125* 2.49 18,129,712 361,144 5.07
1.36 1.99 ALLOY 13 125* 2.94 18,129,712 426,411 6.24 1.89 2.35
*assumed value **for samples that broke during bend testing
Commercial Product Forms
[0068] Due to the combination of properties of the alloys in Table
1, the potential or expected applications for thin products
developed from these alloys may be contemplated. Due to specific
combination of favorable properties, which includes the relatively
high tensile strength and hardness coupled with significant tensile
elongation and high elasticity, it is contemplated that a number of
thin product forms would be viable including fibers, ribbons,
foils, and microwires.
[0069] Reference to thin product forms may be understood as less
than or equal to 0.25 mm in thickness or less than or equal to 0.25
mm in cross-sectional diameter. Accordingly, the range of thickness
may be form 0.01 mm to 0.25 mm, including all values and increments
therein, in 0.01 mm increments. The thin product forms may include,
e.g., sheet, foil, ribbon, fiber, powders and microwire. One may
utilize the Taylor-Ulitovsky wire making process. The
Taylor-Ulitovsky method is a method for preparing a wire material
by melting a glass tube filled with a metal material by
high-frequency heating, followed by rapid solidification. Details
on the preparation method are described in A. V. Ulitovsky, "Method
of Continuous Fabrication of Microwires Coated by Glass", USSR
patent, No. 128427 (Mar. 9, 1950), or G F. Taylor, Physical Review,
Vol. 23 (1924) p. 655.
[0070] The thin product forms noted above may be specifically
employed for structural/reinforcement type applications, including,
but not limited to composite reinforcement (e.g. placement of the
thin product form in a selected polymeric resin, including either
thermoplastic and non-crosslinked polymers and/or thermoset or
crosslinked type resin). The thin product forms (fibers and/or
ribbons) may also be used in concrete reinforcement. In addition,
the thin product forms may be used for wire saw cutting, weaving
for ballistic resistance applications and foil for ballistic
backing applications.
[0071] The thickness of the materials produced may preferably be in
the sub-range of 0.02 to 0.15 mm. In Table 13, a list of commercial
processing techniques, their material form, typical thickness, and
estimated cooling rates are shown. As indicated, the range of
thickness possible in these commercial products is well within the
capabilities of the alloys in Table 1. Thus, it is contemplated
that ductile wires, thin sheets (foils), and fibers may be produced
by these and other related commercial processing methods.
TABLE-US-00014 TABLE 13 Summary of Existing Commercial Processing
Approaches Process Material Form Typical Thickness Cooling Rate
Melt-Spinning/ Ribbon 0.02 to 0.20 mm ~10.sup.4 to ~10.sup.6 K/s
Jet Casting Commercial Process Wire Casting Circular cross 0.3 to
0.15 mm ~10.sup.5 to ~10.sup.6 K/s Process section wire Taylor-
Round wire 0.02 to 0.10 mm ~10.sup.3 to ~10.sup.6 K/s Ulitovsky
Wire Casting Process Planar Flow Thin sheet/foil 0.02 to 0.08 mm
~10.sup.4 to ~10.sup.6 K/s Casting Sheet Process Gas/Centrifigal
Spherical 0.01 to 0.250 ~10.sup.4 to ~10.sup.6 K/s Atomization
powder * Range of thickness where ductile response can be
maintained
Example #1
[0072] Using high purity elements, three fifteen gram charges of
the ALLOY 11 chemistry was weighed out according to the atomic
ratio's in Table 1. The mixture of elements was placed onto a
copper hearth and arc-melted into an ingot using ultrahigh purity
argon as a cover gas. After mixing, the resulting ingots were cast
into a figure shape appropriate for melt-spinning. The cast fingers
of ALLOY 11 were then placed into a quartz crucible with a hole
diameter nominally at 0.81 mm. The ingots were heated up by RF
induction and then ejected onto a rapidly moving 245 mm copper
wheel traveling at wheel tangential velocity of 16 m/s, 10.5 m/s,
and 5 m/s. DTA/DSC analysis of the as-solidified ribbons were done
at a heating rate of 10.degree. C./min and were heated up from room
temperature to either 900.degree. C. or 1350.degree. C. DTA curves
of the three ribbon samples are shown in FIG. 18 and their
corresponding DSC data for the glass crystallization peaks are
shown in Table 14. As shown, by changing the wheel tangential
velocity, the amount of glass and corresponding crystallinity can
be changed from a very high (approaching 100%) percent glass at 20
m/s to a very low value (approaching 0%) at 5 m/s.
TABLE-US-00015 TABLE 14 DSC Results on ALLOY 11 Ribbons Peak Peak
Peak Wheel #1 #1 #2 Peak #2 Speed Glass Onset Peak Enthalpy Onset
Peak Enthalpy (m/s) Present (.degree. C.) (.degree. C.) (-J/g)
(.degree. C.) (.degree. C.) (-J/g) 20 Yes 434 445 51.8 473 478 84.6
16 Yes 439 449 13.0 475 480 24.6 10.5 Yes 437 447 30.6 475 480 53.8
5 No
Example #2
[0073] Using high purity elements, a fifteen gram charge of the
ALLOY 11 chemistry was weighed out according to the atomic ratio's
in Table 1. The mixture of elements was placed onto a copper hearth
and arc-melted into an ingot using ultrahigh purity argon as a
cover gas. After mixing, the resulting ingot was cast into a figure
shape appropriate for melt-spinning. The cast finger of ALLOY 11
was then placed into a quartz crucible with a hole diameter
nominally at 0.81 mm. The ingot was heated up by RF induction and
then ejected onto a rapidly moving 245 mm copper wheel traveling at
a wheel tangential velocity of 16 m/s. The ribbons that were
produced were then annealed in a vacuum tube furnace at 450.degree.
C. for 3 hours. Samples of ALLOY 11 in both the as-spun and
annealed condition were tested using two point bending. The results
of two-point bending are shown in FIG. 19 and tabulated in Table
15. Note that for the as-sprayed samples that the majority of these
samples did not break during testing and folded completely back
against itself as shown in FIG. 20. Note that the lower limit of
the two point bend machine was set at 120 microns and the ALLOY 11
measured ribbon thickness was .about.53 microns. Thus, when the
ribbon was folded completely upon itself it underwent a .about.97%
strain on the side in tension. Note that after the particular heat
treatment chosen, the failure strength and strain for the ALLOY 11
sample both decreased.
TABLE-US-00016 TABLE 15 Results of Bend Testing on ALLOY 11 in the
As-Spun and Annealed Conditions Youngs Failure Youngs Failure Avg
Max Modulus Strength Modulus Strength Weibull Strain Strain Alloy
Condition (GPa) (GPa) (psi) (psi) Modulus (%)* (%) ALLOY As-Spun
133.0 2.67 19,292,915 385,800 10.1 1.87 97 11 ALLOY Annealed 133.0
2.25 19,292,915 325,112 4.9 1.05 1.47 11 *for samples that broke
during bend testing
Example #3
[0074] Ribbon samples of ALLOY 11 melt-spun at 16 m/s and prepared
according to the methodology in Example #1 were utilized for
additional two point bend testing. By opening and closing the
faceplates and visually inspecting the samples, it was possible to
visually determine the onset of plastic deformation to look for
permanent deformation. When the samples were bent at 2.4% strain
and below, no permanent deformation was observed on the ribbon as
it appeared to completely spring back. While deforming the ribbon
from 2.4% to 2.6%, permanent deformation was observed with the
ribbon containing a slight kink after testing (see arrow in FIG.
21). This example indicates that the materials may exhibit a
relatively high elasticity, which may be consistent with their
metallic glass nature. Note that conventional crystalline materials
would generally exhibit an elastic limit below 0.5%.
[0075] The foregoing description of several methods and embodiments
has been presented for purposes of illustration. It is not intended
to be exhaustive or to limit the claims to the precise steps and/or
forms disclosed, and obviously many modifications and variations
are possible in light of the above teaching. It is intended that
the scope of the invention be defined by the claims appended
hereto.
* * * * *